California's Rim-Fire is now 30% contained. Fire fighters expect full containment by September 10.

Firefighters now have 30 percent of California's Rim Fire contained with full containment expected by Sept 10. While hot weather and aggressive winds have stymied efforts to control the fire, a reversal of climate conditions, combined with increased moisture in the air, have helped firefighters make significant progress.

"[The weather has] given us a greater opportunity to get in there and strengthen our containment lines," Cal Fire spokesman Daniel Berlant told The Los Angeles Times.

The weather's role has been critical: in two separate 24 hour periods last week the fire burned 30,000 and 50,000 acres. In contrast, in two days this week, the fire burned 10,000 and 5,000 acres. In total, the fire has destroyed more than 40,000 acres in Yosemite National Park and 187,000 acres overall.

(Photo: Google Maps/InciWeb)

This map shows the Rim Fire's current position as at 4 p.m. ET on Thursday August 29, 2013.

On the ground, fire crews have tried to slow the fire from spreading to the Hetchy Hetchy Reservoir, a major water source for the city of San Francisco. In order to rid the ground of would-be Rim Fire tinder, firefighters have set plants, brush and combustible items within containment lines ablaze.

Firefighters on Wednesday also began using a drone to provide a big picture view of the blaze. The drone captured real time images, provided a map of the 300-square-mile blaze and offered data about the direction the fire was moving, the magnitude of containment and confirmation of new fires.

Previously, fire officials had relied on helicopters that were forced to refuel every two hours. In contrast, the drone surveyed the Rim Fire for 22 hours.

"The drone is providing data directly back to the incident commander, allowing him to make quick decisions about which resources to deploy and where," Berlant said.

Despite their value to fire crews, drones cost $800 an hour, and the fact that they cannot fly through strong wind and smoke have often kept them grounded.

More than 4,200 firefighters from federal, state and local agencies have been involved in fighting the fire, a natural disaster that has currently cost $39 million.

The fire, which began on Aug. 17, has already destroyed 111 buildings, including 31 homes, shuttered businesses and scared away a normally high Labor Day tourist population. Evacuations are ongoing, with 4,500 structures still threatened.

Even after the fire is contained within the next two to three weeks, officials expect the blaze to continue to burn until rain arrives in the region.